Classifications

• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
  • A61B17/00—Surgical instruments, devices or methods
  • A61B17/56—Surgical instruments or methods for treatment of bones or joints; Devices specially adapted therefor
  • A61B17/58—Surgical instruments or methods for treatment of bones or joints; Devices specially adapted therefor for osteosynthesis, e.g. bone plates, screws or setting implements
  • A61B17/68—Internal fixation devices, including fasteners and spinal fixators, even if a part thereof projects from the skin
  • A61B17/72—Intramedullary devices, e.g. pins or nails
  • A61B17/7208—Flexible pins, e.g. ENDER pins
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
  • A61B17/00—Surgical instruments, devices or methods
  • A61B17/16—Instruments for performing osteoclasis; Drills or chisels for bones; Trepans
  • A61B17/17—Guides or aligning means for drills, mills, pins or wires
  • A61B17/1717—Guides or aligning means for drills, mills, pins or wires for applying intramedullary nails or pins

Definitions

• the invention relates to an intramedullary, longitudinal implant as well as to a guide sleeve for insertion of the implant into the intramedullary space of a bone.
• intramedullary load supports e.g. intramedullary nails, locked intramedullary nails and so on are implanted in the marrow space by means of hammer strokes or through axial pressure onto the nail end.
• the forces generated by such implantation methods are directly transferred to the bone through frictional and normal forces.
• the magnitude of the generated forces depends on many factors, including the diameter of the marrow space relative to the diameter of the nail as well as on the location of the entrance of the nail relative to the longitudinal axis of the marrow space.
• the marrow space may be intraoperatively bored by means of a reamer as far as its diameter is 1 - 2 mm greater than the diameter of the nail. This reaming procedure reduces the forces to be applied during implantation of the nail, but has deleterious effects on endosteal blood flow.
• a reduction of the forces generated during implantation or explantation of the nail by using an entry location which is in line with the center of the medullary space and which allows a nail insertion parallel to the longitudinal axis of the bone is problematic.
• This problem arises in case of intramedullary nailing of most of the tubular bones since the longitudinal axis of these tubular bones extends either through a bone joint (knee joint, shoulder joint, elbow joint) or through critical soft tissue like attachments of tendons or blood vessels (hip joint).
• a curved entry channel from the surface of the bone to the intramedullary space allows to pass articulate surfaces or critical soft tissue.
• the respective intramedullary nails are slightly angled in the region of the nail end (Herzog's curvature in case of tibia nails, curved nail end of humerus nails, double curvature in case of femur nails and so on).
• the nail must be elastically deformed due to the entry channel being eccentric to the axis of the marrow space until the curvature of the nail end which corresponds to the entry channel immerges in the bone.
• the force being necessary to elastically deform the intramedullary load support so far that it may compensate the deviation of the shape of the marrow channel entirely acts on the bone. Load peaks arise at the nail insertion site as well as in the region where the nail tip reaches the inner wall of the bone.
• the invention intends to provide remedial measures.
• the invention is based on the objective of providing an intramedullary, longitudinal implant as well as a guide sleeve being apt for insertion of the implant into the marrow space, which permit to absorb the forces being generated during the elastic deformation of the implant upon implantation or explantation therewith protecting the bone. Due to this protective function the nail insertion sites may be adapted to the anatomical conditions without risking an overstressing of the bone during implantation or explantation.
• the invention solves the posed problem with an intramedullary, longitudinal implant that comprises a curved first end portion with coupling means being attachable to a nail insertion unit, and a second end portion being elastically bendable, such that it can assume a curvature equivalent to the curvature of the first end portion without being permanently deformed.
• the nail insertion unit or nail extraction unit respectively generates the necessary force to insert and/or remove the nail.
• both elements form a unit or the elements are mutually connectable.
• the nail deviating sleeve consists of a tube which forms circular arc like a circular sector.
• the uniform radius of the tube defined therewith is essential for the function of the nail deviating sleeve. Nevertheless, the diameter of the tube, the diameter of the circular arc as well as the length of the circular arc is dependent on the application.
• a stop being provided at the lateral end of the circular arc defines the desired depth of insertion of the nail deviation sleeve.
• a coupling for the nail insertion/extraction instruments is situated at the lateral end of the sleeve or else the sleeve and the instrument form a unit.
• the intramedullary nail must be adapted to the circular arc of the nail deviation sleeve in the region of the nail end, i.e. the diameter of the nail may be maximum equal or preferably a little smaller than in interior diameter of the nail deviation sleeve.
• the radius of the circular like nail curvature at the end of the nail may be identical with the radius of the nail deviation sleeve.
• the length of the circular arc at the nail end is independent of the length of the circular arc of the nail deviation sleeve, but is dependent of the respective anatomy of the bone to be treated.
• the portion of the nail being apart from the circular arc must have a sufficient elasticity in order to insert the nail during implantation through the deviation sleeve into the marrow space without the nail being permanently deformed, i.e. the nail shape is identical before and after the implantation.
• a sufficient elasticity of the nail is achieved by using elastic materials (synthetics, titan, titan alloys, memory alloys, steel alloys, particularly subsequently treated steel alloys and so on).
• the nail design may additionally influence the elastic behaviour of the nail. As an example, thin-walled tubes, slotted tubes or longitudinally folded tubes and so on may be applied.
• the above mentioned embodiments of the nail are essential to insert the nail through the nail deviation sleeve into the marrow space of a tubular bone. Due to the circular arc like curvature at the nail end the nail is situated in the marrow space without undesired advance bending load. If desired the nail deviation sleeve may be removed without changing the position of the nail end relative to the nail insertion site on the bone.
• the first end portion is formed arc like, especially circular arc like.
• one ore more transverse bore holes are provided in the region of the second end portion permitting a locking of the implant by means of screws.
• the implant may be longitudinally hollow in order to receive a guide wire.
• a guide sleeve apt for receiving and inserting an implant according to the invention into the marrow space of a bone comprises a front end piece, a rear end piece and an intermediary piece situated between the end pieces.
• the guide sleeve being manufactured of a metallic work piece is provided with at least one curvature in the intermediary piece.
• the curvature of the intermediary piece is arc like, preferably circular arc like.
• the front end piece and the rear end piece are at an angle alpha of typically between 20° and 100°, preferably between 30° and 80°.
• the curvature of the intermediary piece is continuous.
• the curvature of the intermediary piece should extend over an arc segment of at least 5°, preferably at least 10°.
• a stop is arranged at the outer periphery of the guide sleeve being apt as a stop at the surface of a bone.
• the latter has an elasticity such that it does not deform permanently after being entirely inserted in the guide sleeve.
• the radius RF of the circular arc like curvature of the intermediary piece is equal to the radius Ri of the circular arc like curvature of the first end portion of the implant, thus permitting the advantage that the implant is not prestressed after removement of the guide sleeve.
• the guide sleeve is preferably manufactured of a synthetic, thus permitting a simple adaptation of the elastic region, particularly in case of composite materials.
• the guide sleeve is preferably apt to be coupled to a driving unit at one of its ends, the driving unit permitting a longitudinal relative movement of an elastic intramedullary implant without transferring longitudinal forces to the guide sleeve.
• Fig. 1 shows a longitudinal section through a guide sleeve according to the invention together with an implant according to the invention in the form of an intramedullary nail;
• Fig. 2 shows a schematic view of the elastic deformation of the implant according to the invention as shown in fig. 1 during implantation of the implant;
• Fig. 3 shows a longitudinal section through the guide sleeve according to the invention together with an intramedullary nail as shown in fig. 1 inserted therein during insertion into the intramedullary space of a bone;
• Fig. 4 shows a longitudinal section through an embodiment of the driving unit according to the invention.
• Fig. 5 shows a magnified view of the cut-out A in fig. 4.
• Fig. 1 and 3 show an implant 1 being configured as an intramedullary nail 30 and a curved guide sleeve 10.
• the intramedullary nail 30 has a leading end 34 and a trailing end 35, with the leading end 34 being configured as a tip.
• said intramedullary nail 30 comprises a curved first end portion 2 including the trailing end 35, a coupling means 3 arranged at said trailing end 35 and an elastically bendable second end portion 5 adjoining said leading end 34. Due to its elasticity said second end portion 5 is bendable from a straight first position into a curved second position, such allowing said second end portion 5 to be passed through said guide sleeve 10.
• the guide sleeve 10 is used as a nail deflection sleeve 40 in the embodiment shown here, such permitting that the intramedullary nail 30 must not be inserted straightway into the intramedullary space of the a bone 4 (fig. 3).
• the elasticity of said second end portion 5 allows a curved insertion into the intramedullary space from a lateral side of the bone. Due to this possibility of a lateral curved insertion of the intramedullary nail 30 the insertion path must not pass through an articulation surface at a longitudinal end of the bone and the entry point for the nail insertion on the surface of the bone may be distant to the articulation surface.
• the two end portions 2;5 axially adjoin each other and are provided with a circular cross-section orthogonal to the longitudinal axis 31 of the intramedullary nail 30.
• the coupling means 3 that are preferably reversibly attachable to a driving instrument 42 (fig. 4) the intramedullary nail 30 may be inserted into or removed from the medullary space of a bone 4 (fig. 3) through the central bore 16 of the guide sleeve 10.
• the second end portion 5 of the intramedullary nail 30 is elastically bendable in order to be bent during insertion through the central bore 16 of the guide sleeve 10 and resiliently straightens after leaving the central bore 16 at the front end 17 of the guide sleeve 10 therewith being slideable into the marrow space 7 of a bone (fig. 3).
• the radius of curvature Ri of the first end portion 2 is equal to the radius of curvature RF of the guide sleeve 10.
• the first end portion 2 of the intramedullary nail 30 has a larger diameter than the second end portion 5.
• the guide sleeve 10 is shaped like a circular arc having a central angle ⁇ of 90° and is further provided with a stop 14 which is located in the axial region of the intermediary piece 13 and may abut the surface 15 of a bone 4 (fig. 3) while a flange 19 arranged at the rear end 18 of the guide sleeve 10 is connectable to a driving unit 20 (fig. 4) which is apt for implantation of the intramedullary nail 30.
• a transverse bore 6 being perpendicular to the longitudinal axis 31 is located which is apt for receiving a locking means, e.g. a screw.
• Fig. 2 schematically shows how the elastic second end portion 5 is elastically deformed during implantation of the intramedullary nail 30.
• the second end portion 5 is elastically bent with the radius R F of the guide sleeve 10 (dashed line).
• the radius of curvature R F of the guide sleeve 10 is equal to the radius of curvature R
• Fig. 4 depicts the first end portion 2 of the implant 1 together with a driving unit 20 comprising a sleeve 41 which is bent on a front segment 47 and which is attachable to the rear end 18 of the guide sleeve 10 (fig. 1), a bendable driving instrument 42 with a screw driver like tip 48 and driving means 49.
• the threaded shaft 44 of the driving means 49 is screwable in a complementary interior thread 45 in the cavity 46 of the sleeve 41 from the free end 43 of the sleeve 41. Thereby, the threaded shaft 44 presses onto the driving instrument 42 which is arranged axially abutting within the sleeve 41.
• the driving instrument 42 is connected to the implant 1 by means of the coupling means 3 (fig.
• the coupling means 3 comprise a bore 23 with an interior thread 22 penetrating from the free end 8 of the first end portion 2 as well as a slot 9 extending diametrally and being located terminally for receiving the screw driver like tip 48 of the driving instrument 42.
• a screw 24 is lead through the central bore 47 of the driving instrument 42 and is screwed into the interior thread 22 such that the driving instrument 42 is fixed at the first end portion 2 of the implant 1.

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• Health & Medical Sciences (AREA)
• Surgery (AREA)
• Orthopedic Medicine & Surgery (AREA)
• Life Sciences & Earth Sciences (AREA)
• Molecular Biology (AREA)
• Animal Behavior & Ethology (AREA)
• Engineering & Computer Science (AREA)
• Biomedical Technology (AREA)
• Heart & Thoracic Surgery (AREA)
• Medical Informatics (AREA)
• Veterinary Medicine (AREA)
• Nuclear Medicine, Radiotherapy & Molecular Imaging (AREA)
• General Health & Medical Sciences (AREA)
• Public Health (AREA)
• Neurology (AREA)
• Dentistry (AREA)
• Oral & Maxillofacial Surgery (AREA)
• Surgical Instruments (AREA)
• Prostheses (AREA)
• Materials For Medical Uses (AREA)

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• 2005
  • 2005-11-08 EP EP05798801A patent/EP1948039B1/de not_active Expired - Lifetime
  • 2005-11-08 CA CA2629044A patent/CA2629044C/en not_active Expired - Fee Related
  • 2005-11-08 AU AU2005338138A patent/AU2005338138A1/en not_active Abandoned
  • 2005-11-08 BR BRPI0520641-3A patent/BRPI0520641A2/pt not_active Application Discontinuation
  • 2005-11-08 KR KR1020087010236A patent/KR101269381B1/ko not_active Expired - Fee Related
  • 2005-11-08 JP JP2008539203A patent/JP5202323B2/ja not_active Expired - Fee Related
  • 2005-11-08 US US12/092,748 patent/US8679120B2/en not_active Expired - Fee Related
  • 2005-11-08 CN CN2005800520170A patent/CN101304694B/zh not_active Expired - Fee Related
  • 2005-11-08 WO PCT/CH2005/000657 patent/WO2007053960A1/en not_active Ceased
• 2006
  • 2006-11-01 TW TW095140342A patent/TWI399191B/zh not_active IP Right Cessation

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